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Experimental Studies on Bicycle Flow Dynamics of Cyclist Loading and Unloading Processes at Bottlenecks


Speaker

Dr. WONG Wai

Department of Civil and Natural Resources Engineering, University of Canterbury

 

Date:    January 4, 2024 (Thursday)

Time:   4:00 pm – 5:00 pm

Venue:  Room 632C, 6/F Haking Wong Building, The University of Hong Kong

 

Abstract

Cycling has emerged as one of the most important green transport modes in recent years, with cities increasingly prioritizing cycling in their sustainable policy agenda. However, the associated traffic dynamics, especially the evolution of bicycle flow at bottlenecks, have not been extensively studied. In this study, real-world experiments were conducted to investigate the dynamics of bicycle flow at bottlenecks under varying cycling demands generated by the cyclist unloading and loading processes. Upon the activation of the bottleneck, its capacity remained largely constant. For the same physical system, the bottleneck capacity of the cyclist loading process exceeded that of the unloading process, indicating the occurrence of capacity drop and hysteresis. Statistical analyses demonstrated that the capacity drop was attributable to the difference in speeds of the two processes for the same cycling demands after the bottleneck activation. These findings could potentially be explained by behavioral inertia. Further analysis revealed that compared with the unloading process, the cyclist loading process was associated with higher cycling speeds owing to the higher overtaking rates. The outcomes of this study can advance our understanding of the physics of bicycle flow dynamics and provide valuable insights for transport planning professionals involved in the facility planning and control of existing networks.

 

About the Speaker

Dr. Wai Wong is a lecturer in the Department of Civil and Natural Resources Engineering at the University of Canterbury, New Zealand. He earned his Ph.D. in transportation and traffic engineering and his bachelor's degree with first-class honours in Civil Engineering both from the Department of Civil Engineering at The University of Hong Kong. Following his graduation, Dr. Wong served as a postdoctoral research fellow at the Department of Civil and Environmental Engineering at the University of Michigan, USA. His research interests include smart city development, big data analytics, intelligent transport systems, cybersecurity and sustainable transport. Fueled by his passion and vision for creating smarter and more efficient transportation systems, Wai has dedicated his research to advancing smart cities through cutting-edge research. He has published in top-tier international journals, including Transportation Science, Transportation Research Part B, Transportation Research Part C, and IEEE Transactions on Intelligent Transportation Systems. He also contributes as a reviewer for these prestigious transportation journals.

 
 
 

Research Cases on the Applications of Data-Driven Methods in Smart Cities

 

Speaker:

Dr. WANG Hai

School of Computing and Information Systems, Singapore Management University

 

Date:    December 28, 2023 (Thursday)

Time:   3:00 pm – 4:00 pm

Venue:  Room 612B, 6/F Haking Wong Building, The University of Hong Kong

 

Abstract

The rapid development and widespread adoption of mobile devices, sensors, IoT, and communication technology have led to the generation of vast volumes of multi-source, high-dimensional data in various systems within the broader framework of smart cities, including transportation, logistics, e-commerce, healthcare, etc. Consequently, numerous data-driven methods have been developed and implemented to address research challenges related to the design and operations of these systems. In this talk, we will briefly discuss several research cases on the applications of data-driven methods in smart cities. These cases include: (1) Descriptive methods for mobile transaction digits distribution and crowd-sourcing food delivery operations; (2) Predictive methods for ICU patient condition evaluation and freelance platform service quality prediction; (3). Prescriptive method for shared transportation ride matching and feeder vessel transshipment routing and scheduling. Through these cases, we aim to showcase the diverse applications of data-driven methods in addressing some key challenges in smart cities.

 

About the Speaker

Dr. WANG Hai is an Associate Professor in the School of Computing and Information Systems at Singapore Management University and a visiting teaching faculty at the Heinz College of Information Systems and Public Policy at Carnegie Mellon University. He is the Singapore PI for the interdisciplinary AI research program at Singapore-MIT Alliance for Research and Technology. He received B.S. from Tsinghua University and Ph.D. in Operations Research from MIT. His research focuses on methodologies of analytics and optimization, data-driven decision-making models, machine learning algorithms, and their applications in smart cities, transportation, and logistics systems. He has published in leading journals such as Transportation Science, American Economic Review P&P, M&SOM, Fundamental Research, and Transportation Research Part B/C/E and has long term collaborations with leading companies such as Meituan, Tencent, DiDi, Grab, and Upwork. He serves as Associate Editor for Transportation Science and Service Science, Special Issue Editor for Transportation Research Part B/Part C, and Service Science, and Editorial Board Member for Transportation Research Part C/Part E. Dr. Wang was selected as Chan Wu & Yunying Rising Star Fellow in transportation and mobility, received Lee Kong Chian Research Excellence Award twice, was nominated for MIT’s top graduate teaching award, and won the Excellent Teaching award for junior faculty at SMU. During his Ph.D. studies at MIT, he also served as the co-President of the MIT Chinese Students & Scholars Association and as Chair of the MIT-China Innovation and Entrepreneurship Forum.


Hosts:

DEPARTMENT OF CIVIL ENGINEERING

JOINTLY ORGANIZED WITH 

HONG KONG SOCIETY FOR TRANSPORTATION STUDIES

And INSTITUTE OF TRANSPORT STUDIES, HKU

 
 
 


Markov Decision Processes in Shared Mobility Operation Problems


Speaker:

Dr. Zheng Zhu

Department of Civil Engineering, Zhejiang University, China

 

Date:    December 28, 2023 (Thursday)

Time:   2:00-3:00 pm

Venue:  Room 612B, 6/F Haking Wong Building, The University of Hong Kong

 

Abstract

The supply-demand imbalance of shared mobility (e.g., ride-sourcing and bike-sharing) is one critical factor that leads to passenger queueing and congestion, idle ride-sourcing vehicles, accumulation of shared bikes, low public transit ridership, and high-level travel costs, so that it restricts the mobility efficiency and social welfare of urban transportation systems. Designing spatial-temporal operation strategies (e.g., pricing, (e)bike rebalancing/recharging, ride-sourcing idle vehicle relocation) can be a feasible approach for mitigating the imbalance. However, concerning the coupling mechanism among supply, demand, and operational strategies, it is difficult to seek smart spatial-temporal strategies via conventional modeling and optimization approaches. Recently, with Markov decision processes (MDPs) and reinforcement learning (RL) have received increasing attention, which have the capability of formulating and solving dynamic optimization problems in complex environments. In this presentation, we show several MDPs the research team has developed for depicting and solving spatial-temporal operational problems in the shared mobility market. Aiming at developing smarter shared mobility systems, we would share our knowledge and experiences for a better understanding of similar problems.

 

About the Speaker

Zheng Zhu, “Hundred Talents Program” Professor, Assistant Head of Department of Civil Engineering at Zhejiang University. Research interests include the planning, design, simulation, management/control and optimization of multi-modal transportation systems. From 2008 to 2021, Zheng has been studying and working at Tsinghua University, University of Maryland, Hong Kong University of Science. He is the principal investigator of 1 Hong Kong Research Grants Committee General Research Fund (RGC-GRF), the participant of 1 Major Research Plan of China National Natural Science Foundation. Zheng has participated in research projects funded by many agencies, such as the US department of transportation (USDOT), the US department of energy (USDOE), US National Science Foundation (NSF), US Federal Highway Administration (FHWA), Aspiration Zealous Force Trustworthy (AZFT), Smart Urban Future (SURF) Laboratory, Zhejiang Province. He has published over 50 SCI papers in top transportation journals such as IEEE TITS, TR Part B, POM, TR Part C, and TR Part E. Zheng serves as the area editor in the annual meeting of the Chinese Overseas Transportation Association (COTA) and an editorial board member in Transportation Safety and Environment.


Hosts:

DEPARTMENT OF CIVIL ENGINEERING

JOINTLY ORGANIZED WITH 

HONG KONG SOCIETY FOR TRANSPORTATION STUDIES

And INSTITUTE OF TRANSPORT STUDIES, HKU

 
 
 
© 2023 by Institute of Transport Studies. The University of Hong Kong.
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